Answer: We know that Heaven is above this earthly plane; the Bible describes God as looking “down” from His heavenly throne: “The Lord is in His holy temple, the Lord’s throne is in heaven” (Psalm 11:4).
Some people may be surprised to learn that the Bible, though, speaks of three heavens. The “first heaven” is simply the earth’s atmosphere (Deuteronomy 11:17; 28:12; Judges 5:4). The “second heaven” is outer space (Psalm 19:4; Jeremiah 8:2; Isaiah 13:10). Understanding this truth is important in helping us clear up many misconceptions.
It is the “third heaven” that most people think of as “Heaven.” This is the Heaven where God the Father resides (1 Kings 8:30; Psalm 2:4; Matthew 5:16).
We read that flesh and blood cannot inherit the Kingdom of Heaven (1 Corinthians 15:50); only Spirit-beings can reside within it. Even a righteous man like King David, whom God called a man after His own heart, is not in Heaven. “For David did not ascend into the heavens” (Acts 2:34). Jesus Christ confirmed this when He said, “No one has ascended into heaven but He who came down from heaven, that is, the Son of Man who is in heaven” (John 3:13). Human beings who have died are now in the grave awaiting resurrection (Ecclesiastes 12:7). Some will be resurrected physically to be judged; others will be resurrected as Spirit-members of the Kingdom of Heaven.
Yes, when Christians are resurrected as Spirit-beings they will inherit all things (Romans 8:32; Revelation 21:7). That inheritance includes access to God the Father in Heaven, even while they serve under Jesus Christ ruling on the Millennial planet Earth!